209 research outputs found

    In vitro effects of regulators on growth and morphogenesis of Ocimum basilicum L. ‘Alfavaca Green’ stem apexes

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    Large-scale cultivation of contamination free plants requires a good standardization protocol and production methods. Basil is widely used for cosmetics, food and pharmaceutical industries as it is rich in many bioactive compounds. This present study aimed to evaluate the growth and in vitro anatomical aspects of apical buds of basil grown under different concentrations rowth regulators like: NAA (Naphthalenoacetic Acid), BAP (6-benzylaminopurine), and KIN (Kinetin). The in vitro establishment was evaluated every 20 days to calculate the, the percentage of plants with calluses, appearance of the roots, any abnormal seedlings, any oxidized seedlings, and the number of sprouts per plant. Growth, physiological, and morpho-anatomical evaluations were performed at 80 days. Basal callogenesis was observed when cytokinin’s and auxins are used in combination. Auxin treatments caused hyperhydricity in the stems and leaves. Medium A2 (0.05 mg L -1 of NAA and 0.1 mg L -1 of BAP), and A3 (0.05 mg L -1 of NAA and 0.1 mg L -1 of KIN) resulted in the best development of basil plants, cultivar ‘Alfavaca Green’. The A2 produced plants with greater numbers of leaves, an average bud length of 59.81 mm, and the best root properties. A2 and A1 have a higher percentage of hyperhydricity (83 and 67%). The A3 resulted in an acceptable number of leaves (range: 21–39), and this treatment produced the best shoot properties as well as fewer plants with hyperhydricity. In addition, the A3 treatment produced plants with a shoot length, high shoot fresh and dry mass (2.82 and 0.23 g), high chlorophyll index and leaf anatomy that was similar to the control. Excluding the control, the other treatments presented more than 90% of the explants with calluses in their bases

    The concept of mass – gravitic and inertial in eurhythmic physics

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    The concept of mass, be it gravitic or inertial, has played a major role in traditional physics. The meaning of the concept of mass and the equivalence between inertial and gravitic mass have been and are object of great polemics in the arena of scientific discussion. In the nonlinear complex inter-relational Eurhythmic Physics, the concept of mass, that has been assumed as a fundamental idea, no longer shares this attribute. In this way of looking at Nature the concept of mass loses its fundamental status being only a relational and, under certain circumstances, useful concept

    Copper modulates the biochemical and enzymatic activity and growth of tomato cultivars grown in vitro

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    Received: August 25th, 2020 ; Accepted: December 17th, 2020 ; Published: February 09th, 2021 ; Correspondence: [email protected] (Cu) is a micronutrient that is neglected for tomato growth. This study sought to identify the effects of exposure to Cu on the growth and biochemical activity of two tomato cultivars. Tomato seeds of ‘Carolina’ and ‘Cereja’ cultivars were disinfected and inoculated in MS medium plus copper sulfate concentrations (CuSO4) (default MS, 25, 50, and 100 µm) and had their growth monitored for 30 days. It was estimated that the growth and biomass accumulation of tomato plants ‘Carolina’ and ‘Cereja’, both from the aerial part and the roots, were benefited by 25 e 50 µm of CuSO4. However, it was observed that these concentrations were inefficient in controlling hyperhydricity and leaf deformation. There was a reduction of these phenomena in the treatment with 100 µm, in both cultivars. Tomato of ‘Carolina’ cultivar subjected to 100 µm showed an increase in anthocyanins and superoxide dismutase (SOD) activity in the root system. There was a reduction of catalase (CAT) activity in shoots exposed to Cu. ‘Cereja’ tomatoes subjected to 100 µm showed an increase in CAT and SOD activity in shoots and roots, respectively. It was concluded that the ‘Carolina’ and ‘Cereja’ tomatoes have their growth impaired when exposed to 100 µm CuSO4. Concentrations higher than 50 µm of CuSO4 cause an increase in the antioxidant activity in the shoot of tomato plants from the ‘Carolina’ cultivar. Concentrations higher than 50 µm CuSO4 increase SOD activity in the root system of tomato plants from the ‘Cereja’ cultivar

    Doniach diagram for ordered, disordered and underscreened Kondo lattices

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    The Doniach's diagram has been originally proposed to describe the competition between the local Kondo effect and the intersite RKKY interactions in cerium compounds. Here we discuss the extension of this diagram to different variations of Kondo lattice model. We consider a) ordered cerium compounds where the competition between magnetic order and Kondo effect plays an important role, as CeRh2Si2CeRh_2Si_2, b) disordered cerium systems with competing spin glass phase, magnetic ordered phases and a Kondo phase, as the heavy fermion cerium alloy CeCuxNi1xCeCu_xNi_{1-x} and, c) uranium compounds where a coexistence between Kondo effect and ferromagnetic order has been observed, as UTe. We show that all these cases can be described by a generalized Doniach phase diagram.Comment: Presented in the Latin American Workshop on Magnetism and Magnetic Materials (LAW3M) Rio de Janeiro, Brazil, August 12-16, 2007. Proceedings to be published in JMM

    Fontes orgânicas de nutrientes em sistemas de produção de batata.

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    Nos últimos anos, diminuiu muito o número de bataticultores na região da Quarta Colônia, no centro do Estado do Rio Grande do Sul (RS), devido ao elevado risco econômico na produção da batata. A partir de uma demanda da Associação dos Produtores de Batata da Região Central do Rio Grande do Sul (ASBAT), foram instalados experimentos visando a avaliar, técnica e economicamente, fontes orgânicas alternativas à adubação mineral tradicional dos produtores de batata, objetivando diminuir os custos de produção e o impacto do seu cultivo no ambiente. Foram estabelecidas rotações envolvendo culturas comerciais e plantas de cobertura de solo para o cultivo da batata na safra e na safrinha. As fontes de nutrientes foram camas de frango e de suínos e adubo mineral tradicionalmente utilizado pelos bataticultores. Os resultados mostraram que a utilização de fontes orgânicas de nutrientes no cultivo da batata é uma alternativa viável técnica e economicamente. Contudo, sua eficiência pode ser maximizada quando associada com a adubação mineral, especialmente para aumentar a quantidade de nitrogênio disponível desde o início do ciclo da cultura e isso é particularmente importante quando do uso da cama de suínos. A cama de frango, por conter maior quantidade de nutrientes, é uma alternativa melhor do que a cama de suínos, tanto técnica quanto economicamente

    Universal Critical Behavior of Aperiodic Ferromagnetic Models

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    We investigate the effects of geometric fluctuations, associated with aperiodic exchange interactions, on the critical behavior of qq-state ferromagnetic Potts models on generalized diamond hierarchical lattices. For layered exchange interactions according to some two-letter substitutional sequences, and irrelevant geometric fluctuations, the exact recursion relations in parameter space display a non-trivial diagonal fixed point that governs the universal critical behavior. For relevant fluctuations, this fixed point becomes fully unstable, and we show the apperance of a two-cycle which is associated with a novel critical behavior. We use scaling arguments to calculate the critical exponent α\alpha of the specific heat, which turns out to be different from the value for the uniform case. We check the scaling predictions by a direct numerical analysis of the singularity of the thermodynamic free-energy. The agreement between scaling and direct calculations is excellent for stronger singularities (large values of qq). The critical exponents do not depend on the strengths of the exchange interactions.Comment: 4 pages, 1 figure (included), RevTeX, submitted to Phys. Rev. E as a Rapid Communicatio

    Generation of vortices and observation of Quantum Turbulence in an oscillating Bose-Einstein Condensate

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    We report on the experimental observation of vortex formation and production of tangled vortex distribution in an atomic BEC of Rb-87 atoms submitted to an external oscillatory perturbation. The oscillatory perturbations start by exciting quadrupolar and scissors modes of the condensate. Then regular vortices are observed finally evolving to a vortex tangle configuration. The vortex tangle is a signature of the presence of a turbulent regime in the cloud. We also show that this turbulent cloud has suppression of the aspect ratio inversion typically observed in quantum degenerate bosonic gases during free expansion.Comment: to appear in JLTP - QFS 200

    Self-similar expansion of the density profile in a turbulent Bose-Einstein condensate

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    In a recent study we demonstrated the emergence of turbulence in a trapped Bose-Einstein condensate of Rb-87 atoms. An intriguing observation in such a system is the behavior of the turbulent cloud during free expansion.The aspect ratio of the cloud size does not change in the way one would expect for an ordinary non-rotating (vortex-free) condensate. Here we show that the anomalous expansion can be understood, at least qualitatively, in terms of the presence of vorticity distributed throughout the cloud, effectively counteracting the usual reversal of the aspect ratio seen in free time-of-flight expansion of non-rotating condensates.Comment: 8 pages, 4 figure
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